Re: Rubin et al: Eccentric Viewing Training for Age-related Macular Disease: Results of a Randomized Controlled Trial (the EFFECT Study)

TO THE EDITOR:

This correspondence is motivated by the need to contextualize the results and conclusions reported by Rubin et al,¹ by introducing a clinical point of view, so that practitioners who provide eccentric viewing training do not lose confidence in the benefits of this practice.

The study by Rubin et al is the fruit of an exceptional effort, both in terms of the number of participants and the application of a protocol enabling an intention-to-treat analysis. In the field of eccentric viewing, the need for rigorous studies is regularly evoked.^2,3 The rigor of the study is unquestionable, and the 4 avenues proposed to explain the lack of improvement in participants' performance are entirely credible, as are the 3 limitations of the study formulated by the authors.

However, the overall impression that emerges from the article is that eccentric viewing training is not beneficial, even though the authors state that they “cannot rule out the potential benefit of training for some people, particularly those in the final stages of the disease” (p.10). The very last sentence of the authors' conclusion, “Our results do not support the routine provision of eccentric viewing training for people with progressing age-related macular disease” (p.10), casts serious doubt on the effectiveness of this practice.

We are not surprised by the lack of performance improvement among the participants in this study. Rather, we would have been greatly surprised if the opposite had been true. In our opinion, the 4 explanations put forward by the authors to justify this lack of progress are sufficient to illustrate the significant gap that exists between a randomized clinical trial context and clinical practice. The authors' explanations are 1) the number of training sessions (low), 2) the experience of those delivering the training (limited), 3) the type of training administered (uniform), and 4) the patient population studied (heterogeneous in terms of visual acuity). We would have liked these explanations to have been given greater prominence in the article so that the reader could have grasped the necessary distinction between the application of a protocol, whose rigor and uniformity are crucial to its validity, and clinical practice, where the client is the focus of attention and where the conditions most conducive to the success of the intervention are met.

In clinical practice, eccentric viewing training is offered to people who meet a number of conditions. Targeted individuals may have visual pathologies other than age-related macular degeneration; they must have visual acuity that results in proven functional limitations, i.e., moderate to severe visual impairment, as defined by the International Classification of Diseases 11th Revision⁴; they have the cognitive abilities to fully understand the concept of eccentric viewing and to master the technique; they formulate needs and objectives that the clinician strives to meet with personalized exercises and training time; and having expressed their needs and objectives, these people have the motivation to devote the effort and time required to make progress. In short, the rehabilitation service provider ensures that the right people are targeted, and that interventions are tailored to each individual.

The Clinical Practice Guideline: Optometric Low Vision Rehabilitation of the Canadian Association of Optometrists⁵ presents eccentric viewing training as part of the visual impairment rehabilitation portfolio. It states that although “Neither the effectiveness of eccentric viewing training nor the effectiveness of one method of eccentric viewing training over another has been well-established […], there is some evidence that eccentric viewing training may improve near VA and vision for general tasks such as shopping or household chores.” (p.32). The guide also states that “[…] interventions that are recommended should not only be task(s) specific, but also patient specific, i.e., tailored for each particular patient's goals, requirements and limitations” (p.38). That is what we are doing in the clinic, and that is how we are making progress.

The authors' conclusion that eccentric viewing training should not be routinely provided is indisputable. Neither people with age-related macular degeneration nor those with other pathologies affecting central vision will benefit from this training if the conditions outlined above are not met. This is where the skillful work of clinicians comes into its own and makes all the difference.